lsa type5:external lsa

通告者:asbr rid-unchanged

范围:整个ospf区域(除nssa)

内容:外部路由

link id:外部路由

命令:show ip ospf data external

show ip ospf border-routers

external(type5)lsas are used to advertise networks from other autonomous systems

type 5 lsas are advertised and owned by the originating asbr

type 5 lsas flood throughout the entire autonomous system.

the advertising router id(asbr)is unchange throughout the autonomous system

type 4 lsa is needed to find the asbr

by default,routes are not summarized.

r5:

router ospf 110

redistribute connected subnets

show ip ospf data external

r3:

show ip route ospf

r5:

router ospf 110

redistribute connected subnets metric-type 1 tag 110

r3:

show ip ospf data summary self

r1:

show ip ospf data

lsa type4:asbr-summary lsa

summary(type 4)lsas are used to advertise an asbr to all other areas in the autonomous system-穿越其他区域时通告asbr的位置

they are generated by the abr of the originating area.

they are regenerated by all subsequentabrs to flood throughout the autonomous system

type 4 lsas contain the router id of the asbr.

r3:

show ip ospf data asbr-summary

修改参考带宽auto-cost reference-bandwidth

r1:

show ip ospf border-routers(查看abr/asbr路由)

路径类型

区域内路径(intra-area path)

区域间路径(inter-area path)

类型1的外部路径(type 1 external path,e1)

类型2的外部路径(type 2 external path,e2)

路径的类型根据下面的次序排列优先级

1.区域内路径

2.区域间路径

3.e1外包路径

4.e2外部路径

router(config-router)#

area area-id range address mask [advertise | not-advertise] [cost cost]

consolidates interatea routes on an abr

router(config-router)#

summary-address ip address mask [not-advertise] [tag tag]

consolidates external routes,usually on an asbr

r5:

int lo1

ip add 55.1.2.1 255.255.255.0

int lo2

ip add 55.1.3.1 255.255.255.0

router ospf 110

summmary-address 55.1.0.0 255.255.252.0

show ip ospf data

no summary-address 55.1.0.0 255.255.252.0

no redistribute connecte subnets

network 55.1.0.0 0.0.255.255 area 1

r3:

show ip route ospf

router ospf 110

area 1 range 55.1.0.0 255.255.252.0(路由来自哪个区域写哪个区域id)

default routes in ospf

a default route is injected into ospf as an external lsa type 5.cost=1

default route distribution is not on by default;use the default-information originate command under the ospf routing process.

r1:

router ospf 110

default-information originate

ip route 0.0.0.0 0.0.0.0 124.1.1.4

show ip ospf neighbor

router ospf 110

default-information originate always